Blowers, Air Pumps or Compressors
Tech Talk 82

Blowers Blowers are designed to provide large volumes of air at low pressure (less than 4 psi). They are commonly used in conjunction with air diffusers and airlifts. This combination adds oxygen and removes carbon dioxide with low power consumption. Typical applications include recirculating fish tank and aquarium systems, bait fish and lobster holding facilities, and shallow pond aeration. Regenerative blowers are preferred in the aquaculture industry because they are the most reliable and economical in this pressure range.

Air Pumps Fractional horsepower Sweetwater® Linear Piston Air Pumps fill the gap between aquarium air pumps and blowers. These units supply up to 5 cfm at depths to 8 feet. Air pumps provide long service life, very quiet operation and very low energy use. They are a perfect fit for koi ponds, bait shop tanks, classrooms, laboratories, etc.

Compressors Sweetwater® oilless rotary vane and piston compressors are used in applications where water depths are greater, such as with lake aeration, algae culture and lobster pounds. These compressors allow airlines tobe run thousands of feet when electricity is not nearthe water. A compressor as little as 3/4 hp can be used to aerate and destratify a 10-acre lake. Compressors used for aquaculture should always be "oilless."

System Sizing
To size a system, first determine the pressure required. Enough pressure is needed to overcome the water pressure at the diffuser’s depth, the piping friction loss, and the diffuser's resistance to airflow.

Example: For a water depth of 36", a low restriction piping system of 4" of water and a low-resistance air diffuser of 10" of water (just prior to cleaning), will require an air pressure of at least 50" of water (36" + 4" + 10"). This is equal to about 2 psi.

The next consideration is the volume of air needed to accomplish the job. If there is only one fish room, one linear air pump compressor with an additional one for emergency back up may be sufficient. In a larger facility, two or more primary blowers or compressors and one emergency back up may be required. When using low-pressure air, it's important that the air piping system and diffusers offer little resistance to air flow (request our bulletin "Air Distribution Systems for Sweetwater® Blowers").

Performance charts and tables are available for all of our blowers and compressors. Selecting the right system for your application is accomplished simply by comparing your pressure and airflow requirements with manufacturer’s performance charts. If you need help, call a Pentair AES technician at 877-347-4788.